Heat exchanger block and a method for wetting a heat exchanger block

ABSTRACT

The invention relates to a heat exchanger block ( 1 ) including a heat exchanger ( 4, 41, 42 ) which is arranged between an inflow surface ( 2 ) and an outflow surface ( 3 ) so that a transport fluid ( 5 ) can be supplied via the inflow surface ( 2 ) to a heat exchanging surface ( 7 ) of the heat exchanger ( 4, 41, 42 ), can be brought into flowing contact with the heat exchanging surface ( 7 ) and can be led away from the heat exchanger ( 4, 41, 42 ) again via the outflow surface ( 3 ) for the exchange of heat between the transport fluid ( 5 ) and a heating agent ( 6 ) flowing through the heat exchanger ( 4, 41, 42 ) in the operating state. In accordance with the invention a perforated coolant lance ( 8 ) is provided so that a coolant ( 9 ) can be introduced between two heat exchanging surfaces ( 7 ) of the heat exchanger ( 4, 41, 42 ) via the coolant lance ( 8 )The invention furthermore relates to a method for wetting a heat exchanger block ( 1 ).

The invention relates to a heat exchanger block as well as to a methodfor wetting a heat exchanger block in accordance with the preamble ofthe independent claims 1 and 13.

The use of heat exchange systems is known in a practically innumerablenumber of applications from the prior art. Heat exchangers are used inrefrigeration systems such as in common domestic refrigerators, inair-conditioning systems for buildings or in vehicles of all kinds,above all in motor vehicles, aircraft and ships, as water coolers or asoil coolers in combustion engines, as condensers or evaporators inrefrigerant circuits and in further innumerable different applicationswhich are all well-known to the person of ordinary skill in the art.

In this respect, there are different possibilities of sensiblyclassifying the heat exchangers from very different applications. Oneattempt is to carry out a distinguishing by the structure or by themanufacture of the different types of heat exchangers.

A division can thus be made by so-called “lamella heat exchangers”, onthe one hand, and “minichannel” or “microchannel” heat exchangers, onthe other hand.

The lamella heat exchangers which have been well-known for a very longtime serve, like all types of heat exchangers, for the transfer of heatbetween two media, e.g., but not only, for the transfer from a coolingmedium to air or vice versa, such as is known, for example, from aclassical domestic refrigerator in which heat is emitted to theenvironment air via the heat exchanger for the production of a coolingcapacity in the interior of the refrigerator.

The environmental medium outside the heat exchanger, that is e.g. water,oil or frequently simply the environmental air which takes up the heat,for example, or from which heat is transferred to the heat exchanger, iseither cooled or heated accordingly in this process. The second mediumcan e.g. be a liquid cold carrier or heat carrier or an evaporating orcondensing refrigerant. In any case, the environmental medium, that ise.g. the air, has a substantially lower heat transfer coefficient thanthe second medium, that is e.g. the refrigerant, which circulates in theheat exchanger system. This is balanced by highly different heattransfer surfaces for the two media. The medium with the high heattransfer coefficient flows in the pipe which has a very enlarged surfaceat which the heat transfer e.g. to the air takes place by thin metalsheets (ribs, lamellae) at the outer side.

FIG. 1 shows a simple example of a lamella heat exchanger 41′ which isknown per se'. In practice, a total heat exchanger block 1′ isfrequently formed by a plurality of such elements in accordance withFIG. 1. In the simplest case, such a lamella heat exchanger 41′ isformed by a plurality of cooling lamellae 413′, whereby the heatexchanging surface 7′ can be hugely increased. In the operating state, aheating agent 6′ flows through the coolant lines 411′ so that theheating agent 6′ can mainly exchange heat with the environment, usuallywith the environmental air 5′, via the cooling lamellae 413′, in thatthe environmental air 5′ is transported as a transport fluid 5′ for thetransport of the heat through the heat exchanger 41′, for example withthe help of a fan, in the direction of the arrow 5′ in accordance withFIG. 1.

It must be pointed out at this point that features of known apparatusfrom the prior art are provided with a dash within the framework of thisapplication, whereas features of embodiments in accordance with theinvention do not have a dash.

The ratio of the outer surface to the inner surface depends in thisrespect on the lamella geometry (=pipe diameter, pipe arrangement andpipe spacing) as well as on the lamella spacing d′. The lamella spacingis selected differently for different applications. However, it shouldbe as small as possible from a thermodynamic aspect, but not so smallthat the pressure loss on the air side is too large. An efficientoptimum is at approximately 2 mm, which is a typical value forcondensers and dry coolers.

The manufacture of these so-called lamella heat exchangers 41′ takesplace in accordance with a standardized process known for a long time.The cooling lamellae 413′ are punched with a press and a special tooland are punched out in accordance with a predetermined scheme and thepunched holes 412′ are provided with collars 414′ for spacings. Thecooling lamellae 413′ are then placed in packets with respect to oneanother. The pipes which should later transport the heating agent 6′,that is the coolant lines 411′, are subsequently pushed into the collars414′ and thus through the punched holes 412′ and are widened eithermechanically or hydraulically so that a very good contact and thus agood heat transfer arises between the coolant line 411′ and the coolinglamellae 413′. The individual pipes are then connected to one another,often soldered to one another, by bends and inlet and outlet pipes. Forreasons of clarity, the inlet and outlet pipes are not shown in FIG. 1.

To illustrate the construction of the heat exchanger 41′ in accordancewith FIG. 1, a section of a plan view of the heat exchanger from thedirection R is shown schematically in FIG. 2. In particular the collars414′ are important through which the coolant lines 411′ are conductedsince it is thereby ensured that the cooling lamellae 413′ maintain adefined spacing d′.

The efficiency is in this respect substantially determined by the factthat the heat which is transferred between the lamella surface and theair has to be transferred to the pipe via heat conduction through thelamellae. This heat transfer is the more effective, the higher theconductivity or the thickness of the lamella is, but also the smallerthe spacing between the pipes is. One speaks of lamella efficiency here.Aluminum is therefore primarily used as the lamella material today whichhas a high heat conductivity (approx. 220 W/mK) at economic conditions.The pipe spacing should be as small as possible; however, this resultsin the problem that many pipes are needed. Many pipes mean high costssince the pipes (made from copper as rule) are considerably moreexpensive than the thin aluminum lamellae. These material costs could bereduced in that the pipe diameter and the wall thickness are reduced,i.e. a heat exchanger is made with a large number of small pipes insteadof with a few larger pipes. This solution would be idealthermodynamically: Very many pipes at small distances with smalldiameters. A substantial cost factor is, however, also the working timefor the widening and soldering of the pipes. It would increase extremelywith such a geometry.

A new class of heat exchangers, so-called minichannel or alsomicrochannel heat exchangers, was therefore already developed some yearsago which are manufactured using a completely different process andalmost correspond to the ideal of a lamella heat exchanger: many smallpipes at small intervals.

Instead of small pipes, however, extruded aluminum sections are used inthe minichannel heat exchanger which have a large number of smallchannels with a diameter of e.g. approximately 1 mm. Such a microchannelheat exchanger block 1′ likewise known per se is shown schematically inFIG. 3. The microchannel heat exchanger block 1′ of FIG. 3 is in thisrespect formed by two heat exchangers 42′ known per se in the form ofextruded sections 42′. The two extruded sections 42′ of FIG. 3 arepreferably in thermal contact with a wavy cooling lamella 413′ so thatthe heating agent 6′, which is conveyed through the microchannels 421′,can better exchange its heat with the transport fluid 5′, preferably air5′, which is, for example, conveyed through the heat exchanger block 1′in the direction of the arrows 5′ by a fan not shown.

In practice in this respect, a heat exchanger block 1′ can alreadymanage, depending on the required heat capacity, with one singleextruded section 42′ as a central heat exchange element. To be able toachieve higher heat transfer capacities, a plurality of extrudedsections 42′ can naturally also be provided simultaneously in one singleheat exchanger block 1′ which are connected to one another, e.g.soldered to one another, in suitable combinations, for example via inletfeeds ad outlet feeds, which is not shown in FIG. 3 for reasons ofclarity.

Such extruded sections can e.g. be manufactured in suitable extrusionprocesses simply and in a variety of shapes from a plurality ofmaterials. However, other manufacturing processes are also known for themanufacture of microchannel heat exchangers such as the assembly ofsuitably shaped sectional metal sheets or other suitable processes.

These sections cannot, and also do not have to, be widened and they arealso not pushed into stamped lamella packets. Instead, for example,sheet metal strips, as explained in FIG. 3, in particular aluminumstrips, are placed between two sections disposed close to one another(common spacings, for example, <1 cm) so that a heat exchanger packetarises by alternating placing of sheet metal strips and sections next toone another. This packet is then soldered completely in a solderingfurnace.

A heat exchanger having a very high lamella efficiency and a very smallfilling volume (inner channel side) arises due to the narrow spacingsand the small channel diameters. The further advantages of thistechnique are the avoidance of material pairings (corrosion), the lowweight (no copper), the high pressure stability (approx. 100 bar) aswell as the compact construction shape (typical depth of a heatexchanger e.g. 20 mm).

Minichannel heat exchangers became established in mobile use in thecourse of the 1990s. The low weight, the small block depth as well asthe limited dimensions required here are the ideal requirements forthis. Automotive radiators as well as condensers and evaporators forautomotive air-conditioning systems are today realized almostexclusively with minichannel heat exchangers.

In the stationary area, larger heat exchangers are usually needed, onthe one hand; on the other hand, the emphasis here is less on the weightand the compact design and more on the ideal price-performance ratio.Minichannel heat exchangers were previously too limited in dimensions tobe considered for this purpose. Many small modules would have had to beconnected to one another in a complex and/or expensive manner. Inaddition, the use of aluminum in the extruded sections is relativelyhigh so that a cost advantage was also practically not be expected fromthe material use aspect.

Due to the high volumes in the automotive sector, the manufacturingprocesses for minichannel heat exchangers have become standardized andhave improved so that this technology can today be called mature. Thesoldering furnace size has also increased in the meantime so that heatexchangers can already be produced in the size of approximately 1×2 m.The initial difficulties with the connection system have been remedied.In the meantime, there are a plurality of patented processes on how theinlet and outlet pipes can be soldered in.

However, above all the price of copper, which has increased greatly withrespect to aluminum, has had the result that this technology is alsobecoming increasingly interesting for stationary use.

In this respect, it has long been known that two to three times moreheat can be dissipated by evaporation of water on air-cooled heatexchanger surfaces than by convection, and indeed at a lower temperaturelevel, because the decisive air temperature in evaporation is thehumidity temperature.

This fact is used inter alia, but not only, with dry coolers. Thehumidifying of the heat exchanger surface takes place in the prior artby spraying by means of nozzles in front of the heat exchanger block onthe air intake side.

The above-described wetting processes may, in another respect, not beconfused with so-called adiabatic cooling. Here, water is atomizedbefore the heat exchanger on the intake side such that the fine waterdroplets are absorbed by the air and the temperature of the air taken indrops to the vicinity of the wet-ball temperature as a consequence ofthe evaporation of the droplets.

This process has a number of problems in practice and is not verypopular with customers for various reasons.

On the one hand, the cooling water cannot be effectively transferred tothe entire heat exchanging surface of the heat exchanger with suchhybrid coolers. On the other hand, in many applications a directapplication of cooling water is indicated. It must thus be taken intoaccount with a condenser in which the upper part is used as a heaterthat this upper part may not be wetted due to the high temperatureswhich occur.

However, this cannot be avoided if, as described above, thehumidification of the heat exchanger surfaces in the known processestakes place by spraying by means of nozzles before the heat exchangerblock at the air intake side.

A further problem results from the fact that the added cooling water issimultaneously also used for cleaning the heat exchanger. For thispurpose, however, it has previously had to be worked with eight totenfold excess water in order effectively to wash out contamination ofthe heat exchanger. This has the result that much more coolant water orcleaning water has to be supplied to the heat exchanger than isultimately vaporized in the actual cooling procedure. The excess coolingwater therefore has to be collected in collection troughs andreprocessed in a laborious manner. In addition, it is feared thataerosols with pathogens can enter into the breathing air via thecollection troughs and can thus be spread.

It is therefore the object of the invention to provide an improved heatexchanger, in particular a hybrid heat exchanger, which overcomes theproblems known from the prior art. This in particular means that a heatexchanger block should be provided by the invention with which heat canbe transferred very effectively and in a very resource saving mannerfrom a heat exchanger to a transport fluid, preferably, but not only, toair, and which can simultaneously be cleaned and operated veryeffectively and in an environmentally friendly manner.

It is furthermore an object of the invention to provide a particularlyeffective method for wetting a heat exchanger block.

The subject matters of the invention satisfying these objects arecharacterized by the features of the independent claims 1 and 13.

The dependent claims relate to particularly advantageous embodiments ofthe invention.

The invention thus relates to a heat exchanger block including a heatexchanger arranged between an inflow surface and an outflow surface sothat the transport fluid can be supplied via the inflow surface to aheat exchanging surface of the heat exchanger, can be brought intoflowing contact with the heat exchanger surface and can be conductedaway from the heat exchanger again via the outflow surface for theexchange of heat between a transport fluid and a heating agent flowingthrough the heat exchanger in the operating state. In accordance withthe invention, a perforated coolant lance is provided so that a coolantcan be introduced between two heat exchanging surfaces of the heatexchanger via the coolant lance.

It is thus an essential recognition of the invention that the heatexchange between the heat exchanger and the transport fluid, that ise.g. between the heat exchanger and air which is conducted through theheat exchanger, can be substantially improved in that a coolant, whichis preferably, but not necessarily, water, is brought directly into theinterior of the heat exchanger via a coolant lance onto the surfaces tobe heat exchanged in the heat exchanger.

For this purpose, in accordance with the invention, a perforated pipe ora perforated or porous hose is provided at the heat exchanger block bywhich the coolant can be introduced between two heat exchanging surfacesof the heat exchanger.

This meant that the heat exchanging surfaces of the heat exchanger canbe wetted with coolant in a direct and controlled manner by the coolantlance. Depending on how the coolant lances are positioned in the heatexchanger, a very uniform cooling capacity can thus be set over thetotal heat exchanger, for example. In another case, e.g. with acondenser, it may be sensible to provide the heat exchanger block onlypartly with coolant lances so that, for example, the part, usually theupper part, of the heat exchanger operated as a heater, for example, isnot additionally cooled by the liquid coolant, whereas the remaining,lower, part is supplied with coolant via the coolant lances.

In this respect, a non-uniform spread of the cooling capacity in theheat exchanger block can naturally also be achieved by other measures.It is thus possible, for example, that different coolant lances are usedin different regions of the heat exchanger block which supply differentquantities of coolant to the different regions. The different coolantlances can thus e.g. have different perforations, that is e.g. differentlarge holes or bores, through which the coolant is introduced betweenthe two heat exchanging surfaces.

It is also possible to use different thick coolant lances so that thethroughput of coolant is different in different regions of the heatexchanger.

The cooling capacity can also be simply and efficiently controlledand/or regulated in dependence on the time with a heat exchanger blockin accordance with the invention in that, for example, the workingpressure of the coolant in all coolant lances or in specific coolantlances is controlled and/or regulator in dependence on the time and/orin dependence on the location.

At the same time, a direct and very efficient cleaning of the heatexchanger block in accordance with the invention is possible by use ofthe coolant lances. Since the coolant is brought into the heat exchangerat the location where it is directly needed, it can be metered verysimply and efficiently and it is in particular not necessary to workwith multifold quantities of excess water. In many cases, a collectiontrough is therefore also omitted since no excess water arises in theoperating state. The formation of polluted aerosols is thereby alsosubstantially prevented and valuable coolant is saved. The laboriouscleaning of excess cooling water is also dispensed with.

It is even possible that, in systems in which in principle no additionalcoolant is required, nevertheless to provide coolant lances inaccordance with the present invention which then only serve for thecleaning of the heating exchanger block.

Either for cleaning during operation in that work is only carried outwith a very small quantity of coolant irrelevant for the cooling. Or,for example, in that the coolant lances are used for cleanings the heatexchanger block in operating breaks.

The wetting method proposed by the present invention thus especiallyincludes the fact that, for example with a lamella heat exchanger, afirst pipe row, viewed in the air direction, is replaced by coolantlances in the form of pipes or porous tubes which are provided withsmall holes or nozzles from which the wetting water, that is thecoolant, exits and is thus introduced into the lamella packet. So thatthe wetting water can spread well over the surfaces of the lamellae, theperforation of the first pipe row of the lamellae or collars, that is ismade without spacers. The pipes or hoses which are used as coolantlances are preferably not widened or otherwise fixed in some manner, butare rather inserted loosely.

A pipe row, in particular a first pipe row, of the lamella packet of theair-cooled heat exchanger can be provided, for example, in part orcompletely, with cooling lances. A part placement is, as alreadymentioned, in particular sensible when the heat exchanger is used as acondenser and the upper part thereof as a heater which may not be wettedwith coolant due to the high temperatures. The regulation of the coolantamount can, if necessary, takes place via the working pressure of thecoolant, for example.

It is understood that instead of only equipping the first pipe row withcoolant lances, the coolant lances can also be positioned in any desiredsensible arrangement in the lamella packet and can be provided with acorresponding perforation.

Instead of removing coolant lines in the lamella packet and replacingthem with coolant lances, which automatically results in a loss of heatexchanging capacity, separate bores can also be provided, preferablywithout collars and specifically with smaller diameters, at the lamellaein a preset arrangement.

Instead of the coolant lances in the form of wetting pipes with holes ornozzles, so-called filter hoses can also be used, also sometimes calledsweating hoses, which clean the coolant, that is, for example, thewetting water, with the degree of purity of the filtered coolantdepending on the quality of the filter hose. The hoses can also becleaned of the filtrate by flushing.

Depending on the application, special coolants or wetting liquids areused instead of normal water, e.g. demineralized or distilled water orwater especially changed in a different manner or, in very specialcases, also other coolants known to the skilled person.

In accordance with the present invention, the same principle cannaturally also be used for the wetting and cooling of microchannel heatexchangers of the initially described kind. The special feature in thisrespect is that here flat pipes are preferably, but not necessarily,used for the wetting which are loosely inserted between the protrudinglamellae after the soldering together of the microchannel heatexchanger. If the coolant lances made as flat pipes were to be solderedtogether with the MPE pipes, there would be the risk that the holes orthe slots of the flat pipe would be closed by solder and would thus nolonger be available for the wetting with coolant.

It is understood that more or less round pipes or hoses can also be usedas coolant lances in a heat exchanger block which is formed frommicrochannel heat exchangers and that, conversely, flat pipes can alsoadvantageously be used as coolant lances in special cases in lamellaheat exchangers.

The heat exchanger is thus made as a lamella heat exchanger in aparticularly preferred embodiment of a heat exchanger block inaccordance with the invention, wherein a coolant line is provided in apunched hole of a coolant lamella.

In an embodiment important for practice, the coolant lance is providedin a separate bore in the cooling lamella so that the number of thecoolant lines is not reduced by the introduction of the coolant lance.In this respect, it is, however, naturally also possible that a coolantline is removed and the coolant lance is provided in the punched hole ofthe coolant lamella.

It is understood that in one and the same heat exchanger coolant linescan in part be replaced by coolant lances and simultaneously separatebores can be provided for further coolant lances.

In a further important embodiment of a heat exchanger block inaccordance with the invention, the heat exchanger is formed by aplurality of microchannels as a microchannel heat exchanger. In thiscase, the coolant lance is preferably a pipe perforated in the form ofholes and/or slits and is in particular provided in the form of a flatpipe.

As already mentioned, in particular when the coolant has to have aspecific purity, a filter hose can be provided as a coolant lance sothat the coolant is automatically purified from specific contaminantsbefore the application to the heat exchanger surface.

For very specific applications, a heat exchanger block in accordancewith the invention can be formed as a combination block of the lamellaheat exchanger and the microchannel heat exchanger. This can be, forexample, when different conditions are present at different locationswith one and the same heat exchanger block and/or when different heatingcapacities have to be provided.

In a manner known per se, a cooling device for cooling the heatexchanger, in particular a fan for generating or amplifying a gas flowof the transport fluid, can naturally additionally be provided betweenthe heating agent and the transport fluid to increase a heat transferrate.

To control and/or regulate the heat exchanger block, a control unitknown per se, in particular a control unit having a data processingdevice, can advantageously be provided for controlling a cooling machineand/or a cooling device and/or the supply of the coolant via the coolantlance and/or an operating parameter or state parameter of the heatingagent and/or another operating parameter of the heat exchanger block.

The heat exchanger and/or the heat exchanger block is/are preferablymade from a metal and/or from a metal alloy, in particular from a singlemetal or from a single metal alloy, in particular from stainless steel,specifically made from aluminum or from an aluminum alloy and/or madefrom a metal combination, e.g. from aluminum and copper, wherein asacrificial metal is preferably provided as corrosion protection and/orwherein the heat exchanger block is provided at least partly with aprotection layer, in particular with a corrosion protection layer.

A heat exchanger block in accordance with the invention can e.g. be acooler, a condenser or an evaporator for a mobile or stationary heatingplant, cooling plant or air conditioning unit, in particular a coolerapparatus for a machine, a data processing device or for a building.

The invention further more relates to a method for wetting a heatexchanger block including a heat exchanger arranged between an inflowsurface and an outflow surface so that a transport fluid is supplied viathe inflow surface to a heat exchanger surface of the heat exchanger, isbrought into flowing contact with the heat exchanging surface and isconducted away from the heat exchanger again via the outflow surface forthe exchange of heat between the transport fluid and a heating agentflowing through the heat exchanger. In accordance with the invention, aperforated coolant lance is provided at the heat exchanger block and acoolant is introduced between two heat exchanging surfaces of the heatexchanger via the coolant lance.

In a preferred embodiment, the heat exchanger is a lamella heatexchanger and/or a microchannel heat exchanger and a regulation of awetting quantity of the coolant is carried out and is preferably carriedout by setting a working pressure of the coolant.

Specifically, the wetting of the heat exchanger with coolant is carriedout for cleaning and/or for increasing the cooling capacity of the heatexchanger.

The invention will be explained in more detail in the following withreference to the drawing. There are shown in a schematic representation:

FIG. 1 a lamella heat exchanger known from the prior art;

FIG. 2 the heat exchanger in accordance with FIG. 1 in section;

FIG. 3 a microchannel heat exchanger known from the prior art;

FIG. 4 a heat exchanger block in accordance with the invention with alamella heat exchanger;

FIG. 5 the heat exchanger in accordance with FIG. 4 in section;

FIG. 6 a heat exchanger block in accordance with the invention with amicrochannel heat exchanger; and

FIG. 7: a coolant lance in the form of a flat pipe.

FIGS. 1 to 3, which show two heat exchangers known from the prior art,were already initially discussed in detail and therefore no longer needto be looked at separately in the following.

It must be pointed out again as a reminder that the features ofembodiments in accordance with the invention are provided with referencenumerals which do not bear a dash, whereas the reference numerals inFIG. 1 to FIG. 3 which show known heat exchangers are provided withdashes.

A heat exchanger block in accordance with the invention having a lamellaheat exchanger is shown schematically in a perspective representation inFIG. 4.

For reasons of clarity, only a lamella heat exchanger 4, 41 is shown ofthe heat exchanger block in accordance with FIG. 4, which is labeled intotal in the following by the reference numeral 1. It is understood thatin practice the heat exchanger block 1 as a rule has even furthercomponents in a manner known per se such as fans, further heatexchangers 4, 41, collection lines as well as inflow and outflow linesfor a heating agent 6 which flows through the heat exchanger 4, 41 toexchange heat, etc.

The heat exchanger block 1 in accordance with the invention of FIG. 4includes a heat exchanger 4, 41 arranged between an inflow surface 2 andan outflow surface 3 so that the transport fluid 5 can be supplied viathe inflow surface 2 to a heat exchanger surface of the heat exchanger4, 41, can be brought into flow contact with the heat exchanger surface7 and can be led away from the heat exchanger 4, 41 again via theoutflow surface 3 for the exchange of heat between a transport fluid 5and a heating agent 6 flowing through the heat exchanger 4, 41 in theoperating state. In this respect, in accordance with the presentinvention, the heat exchanger block 1 includes a perforated coolantlance 8 so that a coolant 9 can be introduced between two heatexchanging surfaces 7 of the heat exchanger 4,41 via the coolant lance8.

In the specific embodiment of FIG. 4, the heat exchanger 4 is made as alamella heat exchanger 41. As already initially described in detail inthe discussion of the prior art, coolant lines 411 are provided in amanner known per se in punched holes 412 of the cooling lamellae 413.

The lamella heat exchanger 41 is thus formed by a plurality of coolinglamellae 413, whereby the heat exchanger surface 7 is hugely increased.In the operating state, a heating agent 6 flows through the coolantlines 411 so that the heating agent 6 can exchange heat with theenvironment, usually with the environmental air 5, mainly via thecooling lamellae 413, in that the environmental air 5 is transported asa transport fluid 5 for the transport of the heat through the heatexchanger 41, for example with the help of a fan not shown in FIG. 4, inthe direction of the arrow 5′.

In the example of FIG. 4, coolant lines 411 selected in accordance witha preset scheme have been removed from their punched hole 412 or havenot been inserted into the associated punched holes 412 in the firstplace on the manufacture of the heat exchanger 41. Instead, coolantlances 8 have been provided in these punched holes 412 of the coolinglamellae 413 through which coolant 9, frequently water 9 in practice,preferably, but not necessarily demineralized water 9, can be introducedbetween two heat exchanging surfaces 7 of the lamella heat exchanger 41.The collars 414 with which a presettable spacing can be set between thecooling lamellae 413 and through which the cooling lines are conductedhave likewise been removed at the punched holes 412 through which thecoolant lances are guided or have not been inserted in the first placeon the manufacture of the heat exchanger 41. Since the collars 414 atthe coolant lances 8 have been dispensed with, an ideal distribution ofthe coolant over the heat exchanging surfaces 7 is guaranteed.

It is understood that the coolant lances 8 can also be provided in aseparate bore in addition to the existing coolant lines 411 in thecooling lamella 413. This has the great advantage that the heatexchanging capacity of the heat exchanger 41 is practically not reducedby the presence of the coolant lances 8 since the number of the coolantlines 411 remains unchanged by the presence of the coolant lances 8 inthe packing of the coolant lamellae 413.

To illustrate the construction of the heat exchanger 41 in accordancewith FIG. 4, a section of a plan view of the heat exchanger 41 from thedirection

R, as defined in FIG. 4, is shown schematically in FIG. 5. It isimportant to note that the collars 414 are missing at the punched holes412 through which the coolant lances 8 are conducted through the coolinglamellae 413, whereas at the punched holes 412 through which the coolantlines 411 are conducted the collars 414 are also still present in theheat exchanger block 1 in accordance with the invention, whereby it isensured that the cooling lamellae 413 maintain a defined spacing d.

It can be recognized very clearly with reference to FIG. 5 how thecoolant 9 can be ideally introduced and distributed between two heatexchanging surfaces 7 of the heat exchanger 41 by the use of the coolantlances 8.

A further very important embodiment of a heat exchanger block 1 inaccordance with the invention is shown partially and schematically in aperspective representation in FIG. 6. The heat exchanger 4 in accordancewith FIG. 6 is formed by a plurality of microchannels 421 also known, asmentioned as microchannel heat exchangers 42.

Instead of small pipes, as initially mentioned, extruded aluminumsections are used in the microchannel heat exchanger 42 which have alarge number of small channels with a diameter of e.g. approximately 1mm. The heat exchanger block 1 of FIG. 6 is in principle such amicrochannel heat exchanger block 1 known per se, wherein the heatexchanger block 1 in accordance with the invention shown in FIG. 6differs from the known heat exchanger blocks 1′ as shown, for example,in FIG. 3, in that here a perforated coolant lance 8 designed in theform of a flat pipe 8 is present, whereas this was previously unknown inthe prior art.

The microchannel heat exchanger block 1 of FIG. 6 is formed in a mannerknown per se by two or more heat exchangers 42 known per se in the formof extruded sections 42. Oppositely disposed extruded sections 42 ofFIG. 6 are preferably in thermal contact with a wavy cooling lamella 413so that the heating agent 6, which is conveyed through the microchannels421, can better exchange its heat with the transport fluid 5′,preferably air 5, which is, for example, conveyed through the heatexchanger block 1 in the direction of the arrows 5 by a fan not shown.

In practice in this respect, a heat exchanger block 1 can alreadymanage, depending on the required heat capacity, with only one pair ofextruded sections 42 as a central heat exchanging element. To be able toachieve higher heat transfer capacities, a plurality of extrudedsections 42′ can naturally also be provided simultaneously in one singleheat exchanger block 1 which are connected to one another, e.g. solderedto one another, in suitable combinations, for example via inlet feeds adoutlet feeds, which is not shown in FIG. 6 for reasons of clarity.

In the heat exchanger block 1 of FIG. 6, a flat pipe 8 is provided whichis perforated in the form of holes 81 and/or slits 81 and which, asshown, is inserted between two extruded sections so that coolant can beapplied from the flat pipe 8 over the heat exchanging surfaces 7 whichare arranged in wavy form between two oppositely disposed extrudedsections 42.

Such a perforated flat pipe 8 is shown again separately in FIG. 7 forillustration. The flat pipe is provided at the side which faces the heatexchanging surfaces of the heat exchanger block 1 in the installed statewith a plurality of perforations, that is holes or slits, so that thecoolant 9 can be applied ideally over the heat exchanging surfaces inthe operating state.

It is understood that in specific cases, instead of perforated flatpipes 8, perforated round pipes 8, perforated hoses 8 or also filterhoses 8, in particular sweating hoses 8, or any other coolant lance 8,can also advantageously be used in a heat exchanger block 1 inaccordance with the invention, even if the heat exchanger block 1 ismade up of microchannel heat exchangers 42.

It is understood that the embodiments described within the framework ofthis application are only to be understood as examples. This means thatthe invention is not solely restricted to the specific embodimentsdescribed. All suitable combinations of the presented specialembodiments are in particular likewise covered by the invention.

1. A heat exchanger block including a heat exchanger (4, 41, 42) whichis arranged between an inflow surface (2) and an outflow surface (3) sothat a transport fluid (5) can be supplied via the inflow surface (2) toa heat exchanging surface (7) of the heat exchanger (4, 41, 42), can bebrought into flowing contact with the heat exchanging surface (7) andcan be led away from the heat exchanger (4, 41, 42) again via theoutflow surface (3) for the exchange of heat between the transport fluid(5) and a heating agent (6) flowing through the heat exchanger (4, 41,42) in the operating state, characterized in that the heat exchangerblock includes a perforated coolant lance (8) so that a coolant (9) canbe introduced between two heat exchanging surfaces (7) of the heatexchanger (4, 41, 42) via the coolant lance (8).
 2. A heat exchangerblock in accordance with claim 1, wherein the heat exchanger (4) is madeas a lamella heat exchanger (41), wherein a coolant line (411) isprovided in a punched hole (412) of a cooling lamella (413).
 3. A heatexchanger block in accordance with claim 2, wherein the coolant lance(8) is provided in a separate bore in the cooling lamella (413).
 4. Aheat exchanger block in accordance with claim 2, wherein a coolant line(411) is removed and the coolant lance (8) is provided in the punchedhole (412) of the coolant lamellae (413).
 5. A heat exchanger block inaccordance with claim 1, wherein the heat exchanger (4) is formed by aplurality of microchannels (421) as a microchannel heat exchanger (42).6. A heat exchanger block in accordance with claim 5, wherein a pipe(8), in particular a flat pipe (8), perforated in the form of holes (81)and/or slits (81) is provided as the coolant lance (8).
 7. A heatexchanger block in accordance with claim 1, wherein a filter hose isprovided as the coolant lance (8).
 8. A heat exchanger block inaccordance with claim 1, wherein the heat exchanger block is formed as acombination block of the lamella heat exchanger (41) and themicrochannel heat exchanger (42).
 9. A heat exchanger block inaccordance with claim 1, wherein a cooling device for cooling the heatexchanger (4, 41, 42), in particular a fan for generating a gas flow, isprovided to increase a heat transfer rate between the heating agent (6)and the transport fluid (5).
 10. A heat exchanger block in accordancewith claim 1, wherein a control unit, in particular a control unithaving a data processing device for controlling a cooling machine and/ora cooling device and/or the supply of the coolant (9) via the coolantlance (8) and/or an operating parameter or state parameter of theheating agent (6) and/or another operating parameter of the heatexchanger block, is provided for controlling and/or regulating the heatexchanger block.
 11. A heat exchanger in accordance with claim 1,wherein the heat exchanger (4, 41, 42) and/or the total heat exchangerblock is/are made from a metal and/or from a metal alloy, in particularfrom a single metal or from a single metal alloy, in particular fromstainless steel, is specifically made from aluminum or from an aluminumalloy and/or made from a metal combination, e.g. from aluminum andcopper, wherein a sacrificial metal is preferably provided as corrosionprotection and/or wherein the heat exchanger block is provided at leastpartly with a protection layer, in particular with a corrosionprotection layer.
 12. A heat exchanger block in accordance with claim 1,wherein the heat exchanger block is a cooler, a condenser or anevaporator for a mobile or stationary heating plant, cooling plant orair conditioning system, in particular a cooler apparatus for a machine,a data processing device or for a building.
 13. A method for wetting aheat exchanger block (1) including a heat exchanger (4, 41, 42) which isarranged between an inflow surface (2) and an outflow surface (3) sothat a transport fluid (5) is supplied via the inflow surface (2) to aheat exchanging surface (7) of the heat exchanger (4, 41, 42), isbrought into flowing contact with the heat exchanging surface (2) and isled away from the heat exchanger (4, 41, 42) again via the outflowsurface (3) for the exchange of heat between a transport fluid (5) and aheating agent (6) flowing through the heat exchanger (4, 41, 42),characterized in that a perforated coolant lance (8) is provided at theheat exchanger block and a coolant (9) is introduced between two heatexchanging surfaces (7) of the heat exchanger (4, 41, 42) via thecoolant lance (8).
 14. A method in accordance with claim 13, wherein theheat exchanger (4) is a lamella heat exchanger (41) and/or amicrochannel heat exchanger (42) and a regulation of a wetting quantityof the coolant (9) is carried out, preferably by setting a workingpressure of the coolant (9).
 15. A method in accordance with claim 14,wherein the wetting of the heat exchanger (4, 41, 42) is carried outusing coolant (9) for cleaning and/or for increasing the coolingcapacity of the heat exchanger (4, 41, 42).